Prophylactic use of canine parvovirus monoclonal antibody induces blockade of vaccinal canine parvovirus immunization similar to maternally derived passive immunity.

OBJECTIVE

To determine initial antibody titer, degradation profile, and duration of passive antibody blockade of active immunization by modified-live viral (MLV) canine parvovirus (CPV-2) vaccine following CPV monoclonal antibody (CPMA) prophylactic subcutaneous (SC) administration to CPV-2-naïve puppies.

METHODS

Purpose-bred, CPV-2-seronegative male and female Beagle dogs, 7 to 8 weeks of age, were randomized to CPMA treatment (n = 13) and control (7) groups. Dogs were commingled and group housed in a shower-in/shower-out facility. At study day 0, dogs were administered either 0.1 mL/kg body weight CPMA SC or an equivalent volume of saline. Sera collected weekly over 140 days were assayed via hemagglutination inhibition and serum virus neutralization. All dogs were administered a commercially available MLV vaccine containing CPV-2 in combination with other core vaccine viruses at 3-week time points beginning at study day 42.

RESULTS

All control dogs remained seronegative through day 42 and seroconverted to CPV-2 after the initial dose of MLV vaccine. By study day 1, the CPMA-treated group showed a mean passive hemagglutination inhibition titer of 1,674. The average degradation rate was calculated at R2 = 0.97, with a mean half-life of 18.9 days. Twelve of 13 (92%) in the treated group seroconverted after a fourth vaccination on day 105.

CONCLUSIONS

Prophylactic CPMA at 0.1 mL/kg body weight SC can block active CPV-2 immunization for 15 weeks when given to seronegative puppies.

CLINICAL RELEVANCE: Initial puppy vaccination series should be extended after CPMA prophylactic use.